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1) All of the following can be classified as biomolecules except

A) lipids.

B) proteins.

C) carbohydrates.

D) nucleic acids.

E) All of the above are biomolecules.

2) Which functional group is least important in biochemistry?

A) amine B) ester C) hydroxyl D) aromatic E) amide

3) The protein configuration that is primarily determined from interactions between R groups is the

A) primary structure.

B) tertiary structure.

C) quaternary structure.

D) secondary structure.

E) none of the above

4) All of the following are major functions of proteins except

A) transport of necessary chemicals.

B) support for organs or tissues.

C) protection against foreign substances.

D) storage of energy.

E) control of biochemical reactions.

5) Members of which class of biomolecules are the building blocks of proteins?

A) fatty acids

B) glycerols

C) amino acids

D) monosaccharides

E) nucleic acids

6) The peptide bond joining amino acids into proteins is a specific example of the ________ bond.

A) amide B) ester C) glycosidic D) carbonyl E) hydrogen

7) Serum albumin is an example of a(an)

A) enzyme.

B) transport protein.

C) protective protein.

D) structural protein.

E) storage protein.

8) Collagen is an example of a(an)

A) structural protein.

B) transport protein.

C) hormone.

D) enzyme.

E) storage protein.

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10) Which molecule is an alpha amino acid?

A)

B)

C)

D)

E)

11) The side chains or R groups of amino acids can be classified into each of the following categories

except

A) basic.

B) acidic.

C) polar.

D) non-polar.

E) isoelectric.

12) Which category of amino acid contains R groups that are hydrophobic?

A) non-polar

B) acidic

C) basic and acidic

D) basic

E) polar

13) Which amino acid is a secondary amine with its nitrogen and the alpha-carbon joined as part of a

ring structure?

A) proline B) arginine C) glycine D) lysine E) histidine

9) Insulin is an example of a(an)

A) enzyme. B) transport protein. C) hormone. D) storage protein. E) structural protein.


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14) Non-polar R groups on amino acids are said to be ________ because they are not attracted to water

molecules.

15) Polar R groups, along with acidic and basic R groups, are said to be ________ because they are

attracted to water molecules.

A) ionized

B) hydrophilic

C) unreactive

D) hydrophobic

E) none of these

16) Two functional groups that are present in all amino acids are the ________ group and the ________

group.

A) hydroxyl; amide

B) carboxyl; phosphate ester

C) acetal; amine

D) carboxyl; amine

E) carbonyl; amide

17) An amino acid whose R group is predominantly hydrocarbon would be classified as

A) non-polar.

B) basic.

C) isoelectric.

D) acidic.

E) polar.

18) Which amino acid is classified as neutral and non-polar?

A) aspartic acid

B) tyrosine

C) phenylalanine

D) lysine

E) histidine

19) Which amino acid is classified as basic?

A) threonine

B) valine

C) glutamic acid

D) phenylalanine

E) lysine

20) Amino acids found in proteins all have the following features.

A) all are D- amino acids

B) all are L-amino acids

C) all are α-amino acids

D) all are correct

E) none are correct

A) hydrophobic B) hydrophilic C) unreactive D) ionized E) none of these


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22)

This question has four parts:

a. For the amino acid shown above in zwitterion form, circle the carboxyl group, underline

the amine group, label the alpha carbon, and draw a box around the R group.

b. Write the name and abbreviation of your amino acid.

c. Classify the amino acid as polar, non-polar, acidic, or basic. Explain the basis for your

classification.

d. Draw the structure of the amino acid at a pH well below its isoelectric point and well

above its isoelectric point.

21) Which of these amino acids has a thiol group as part of its side chain?

A) threonine B) histidine C) methionine D) tyrosine E) cysteine

23) Which structure represents a zwitterion?

A)

B)

C)

D)

E)


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26) An amino acid will have the form shown at

E) a ping-pong ball

31) Which molecule is chiral?

A) CH2Cl2

B) CH3OH

C) CH3CH2OH

D) CHCl2Br

E) CHFClBr

30) Which amino acid is not chiral?

A) arginine B) cysteine C) glycine D) phenylalanine E) alanine

29) Which object is not chiral?

A) a dog B) a clock C) a truck D) a thumbtack E) a boot

27) Proteins are least soluble in water ________.

A) at high pH B) at low pH C) at their isoelectric point

D) at neutral pH E) at both high and low pH

28) Which of the following objects is chiral?

A) a fork B) a windowpane

C) a nail D) a shoe

A) its isoelectric point. B) a pH greater than its isoelectric point.

C) a pH of 7.0. D) any pH other than 7.0.

E) a pH less than its isoelectric point.

b

a.

24) The isoelectric point of an amino acid is

A) the pH at which it exists in the basic form.

B) the pH equal to its pK

D) the pH at which it exists in the zwitterion form.

E) the pH at which it exists in the acid form.

.

C) the pH equal to its pK

A) a pH greater than its isoelectric point.

B) a pH less than its isoelectric point.

C) any pH other than 7.0.

D) its isoelectric point.

E) a pH of 7.0.

25) An amino acid has the form shown at


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32) Enantiomers are a form of stereoisomer in which each molecule in the pair of isomers has

A) a plane of symmetry perpendicular to the carbon skeleton so that the bottom half and top half

of the molecule are mirror images.

B) its functional groups situated in different configurations with respect to a double bond.

C) the same functional groups, but a different carbon skeleton.

D) the same carbon skeleton and the same functional groups, but the functional groups are

attached at different sites.

E) a carbon atom bonded to four different groups and the isomers are mirror images.

34) The amino acid sequence of a protein is known as its

A) quaternary structure.

B) secondary structure.

C) tertiary structure.

D) primary structure.


35) The tripeptide represented as ala-leu-gly is named

A) alanine-leucine-glycine.

B) alanylglycylleucine.

C) alanine-glycine-leucine.

D) alanylleucylglycine.

E) none of these

36) The N-terminal amino acid in the peptide ala-leu-gly-his-pro is

A) glycine. B) proline. C) leucine. D) histidine. E) alanine.

37) The C-terminal amino acid in the peptide ala-leu-gly-his-pro is

A) histidine. B) proline. C) leucine. D) alanine. E) glycine.

38) How many different tripeptides can be formed from one molecule each of the amino acids tyrosine,

valine, and alanine?

A) 3 B) 12 C) 6 D) 9 E) 24

39) In the tetrapeptide Ala-Cys-Val-Leu, the N-terminal amino acid is ________.

A) Ala

B) Val

C) Cys

D) Leu


33) List three properties of enantiomers that are the same and three properties that aredifferent.


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40) In the tetrapeptide Ala-Cys-Val-Leu, the C-terminal amino acid is ________.

A) Cys

B) Ala

C) Leu

D) Val


41) The two protein chains in insulin are held together by ________.

A) salt bridges

B) hydrophobic interactions

C) disulfide linkages

D) hydrogen bonds

E) all of the above

42) All of the following are non-covalent interactions important in maintaining the secondary, tertiary,

and quaternary aspects of amino acids except

A) hydrogen bonding along the backbone.

B) sulfur-sulfur bonds.

C) hydrophobic interactions between R groups.

D) hydrogen bonding between R groups.

E) salt bridges between R groups.

43) Which amino acid can form covalent sulfur-sulfur bonds?

A) phenylalanine

B) cysteine

C) glycine

D) proline

E) methionine

44) Which pair of amino acids can have hydrophobic interactions?

A) glutamic acid and serine

B) glycine and asparagine

C) aspartic acid and lysine

D) leucine and alanine

E) arginine and glutamic acid

45) Which pair of amino acids can have ionic interactions?

A) glutamic acid and serine

B) glycine and asparagine

C) leucine and alanine

D) asparagine and lysine

E) arginine and glutamic acid

46) Which pair of amino acids can form hydrogen bonds between their R groups?

A) arginine and glutamic acid

B) glutamine and serine

C) aspartic acid and lysine

D) leucine and alanine

E) glycine and asparagine


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47) The beta-pleated sheet is an example of

A) secondary structure.

B) quaternary structure.

C) tertiary structure.

D) primary structure.


48) The type of bond that is most important in maintaining secondary structure of a protein is

A) hydrogen bonding between R groups.

B) hydrophobic interactions.

C) disulfide bridges.

D) salt bridges.

E) hydrogen bonding within the backbone.

49) All of the following are examples of fibrous proteins except

A) wool.

B) insulin.

C) skin.

D) bones.

E) fingernails.

50) All of the following are globular proteins except

A) albumin.

B) hemoglobin.

C) immunoglobulin.

D) ribonuclease.

E) myosin.


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a.

b. leucine, leu

c. Leucine is non-polar because its R group is composed of hydrocarbons.

d. Below its isoelectric point, leucine would be written as

Answer Key

1) E2) D3) B4) D5) C6) A7) B8) A9) C

10) E

11) E

12) A

13) A

14) A

15) B

16) D

17) A

18) C

19) E

20) C

21) E

22) Any amino acid may be drawn in. This question is answered for leucine.

23) A24) D25) A26) E27) C28) D29) D30) C31) E32) E

density

Different: interaction with plan-polarized light, reaction with other chiral molecules, placement of groups in space,

biological activity, odor, taste, other physiological interactions

33) Same: molecular formula, connections between atoms, melting point, boiling point, water solubility, isoelectric point,

34) D35) D36) E37) B38) C39) A40) C41) C42) B43) B44) D45) E46) B47) A48) E

49) B50) E


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